A Rare Case of Human Papillomavirus-associated High-grade Neuroendocrine Carcinoma of the Hypopharynx

We present a case of primary small cell carcinoma of the hypopharynx (SCCH), with a rare association with human papillomavirus (HPV). A comparison is made to 11 previously known, well-documented cases of SCCH with a review of the literature concerning SCCH. Our patient’s age of 23 years is the lowest among all previously reported cases, with an age range of 35-75. HPV association with SCCH is a rare new entity and eight HPV subtypes were identified in our case by ribonucleic acid (RNA) in-situ hybridization. The important common features among the previously reported 11 cases and our case include: (a) piriform sinus of the hypopharynx as the primary site in all cases, (b) a majority of patients presented with dysphagia and a neck mass, and (c) most patients had locoregional involvement at the time of presentation as opposed to distant metastasis. HPV-associated SCCH is extremely rare, with potentially aggressive clinical behavior, and needs much more research to further elucidate both the diagnostic and therapeutic approaches.